As techniques for displaying data in a database, there is known a technique that provides indexes such as B-tree and Hash, and by using those indexes, the database is searched for data, so as to display the retrieved data (e.g., Japanese Unexamined Patent Application Publication No. 2007-25735, referred to as “patent document 1” and Japanese Unexamined Patent Application Publication No. 6-335165, referred to as “patent document 2”).
As techniques of unit conversion of data in a database, there is known a technique that, when data of the database is requested by an application, performs a unit conversion process for converting the unit of data in conformity with the unit used in the application, and provides the converted data to the application that has requested the data (e.g., see International Patent Application Publication No. WO2007/083371).
According to a technique that performs unit conversion of data when data of a database is used, like the aforementioned technique which performs the unit conversion process when data of the database is provided, it is necessary to perform the unit conversion process every time data is used, with respect to individual data. Therefore, a processing load for the unit conversion is heavy, and accordingly, this prevents efficient use of data. By way of example, if large volume of data is utilized, the unit conversion process is performed individually on such large volume of data, resulting in that a long time is required until the unit conversion of data is completed, failing to use data promptly.
An object of the present invention is to perform unit conversion of data in a database, so as to use the data more efficiently.